What do new bpy class naming conventions in Blender 2.80 actually mean?
It seems bl_idname of operators is an exception to this new convention

Looking through Python scripts that come with Blender 2.80 I can see that the convention is followed in bl_idname and class name as described with:


headers( _HT_ )
menus( _MT_ )
panels ( _PT_ )
UI lists ( _UL_ )


but not with operators since that is not possible. Operators sometimes follow this convention in their class names, but never in bl_idname, where they follow the usual categorization with the dot, like bl_idname = "object.randomize_transform". 

That was the confusing part to me since OBJECT_OT_fancy_tool was given as an example without clarification and it would definitely not work as a bl_idname for an operator.